Passive House is a building that does not require much conventional building heating on account of its thermal insulation and airtightness with very energy-efficient windows and ventilation system. Passive house uses more often electrical heating with air heat pump because of low heating energy consumption. However, a passive house can even be connected to a geothermal heat pump.

When compared to average new buildings, passive houses use about 60-75 % less heating energy compared to a regular house. The comparison does not include the heating of household water, which is about the same for both house types.

Passive house is not a registered trademark and term has few different descriptions on different climate zones. In Central Europe, the German Passive House Institute has set international definitions demanding that space heating energy demand should not exceed 15 kWh per square meter of net living space (treated floor area) per year or 10 W per square meter peak demand. The Passive House Institute and its approved local representatives grant certificates for houses that follow the approved rules. In Northern Europe, with a much colder climate, the term “passive house” is used also for houses with slightly different requirement. In Sweden, Norway, and Finland the heating energy demand should not exceed for example between 20-30 kWh per square meter of net living space.

Common for all passive houses is the airtightness value of maximum of 0.6 air changes per hour at 50 Pascals pressure (ACH50). Standards don’t set exact demands on the design features to achieve these goals, but typically the houses need to have well-insulated building envelope for minimal heat losses, compact shape with no thermal bridges, energy-efficient windows facing sun allowing the use of passive solar gains and good air tightness for controlled ventilation and reduction of heat losses. Passive houses demand careful design of structures and implementation.

Passive house designs have been used extensively in residential houses but there are also examples of other types of buildings. Passive house standard doesn’t limit the use of buildings, although some design limitations on corners or large window surfaces may be needed.

Designing buildings to meet the passive house concept is an efficient way to save on running costs. Passive houses are typically only 5-10 % more expensive than conventional ones, but as the heating energy consumption is ca. 75 % lower, the payback times are relatively short. With high energy prices which are likely to rise in the future, life cycle costs are much lower than in a conventional house. Payback time for the very-low energy house, such as a passive house, is approximately 15 years.